Toxic effects of the administration of Mikania glomerata Sprengel during the gestational period of hypertensive rats.

Herbal medicine is an ancient practice that has been gaining acceptance of the medical class through scientific studies that prove its effectiveness. However, its use should still be cautious. Medicinal plants have potential toxic effects not yet discovered, and may have unproven interactions with other medications. The use of drugs during pregnancy is still very dangerous and vigorously studied; however, there are few studies of herbal medicines in pregnant women. Existing studies prioritize on teratogenic or abortifacient effects. The aim of this study was to analyze the toxic effects of Mikania glomerata Sprengel administration, popularly known as "guaco" during the gestational period of hypertensive rats. For this experimental groups consisting of pregnant Wistar rats received treatments with guaco extract (1 to 2 mL). In order to analyze the possible toxic effects of guaco during pregnancy, weight gain of rats was assessed during pregnancy; reproductive performance of rats, morphological parameters, and fetal placental histology were compared. Although some parameters presented significant differences, we can conclude that changes prioritized by literature, such as toxicity, vasodilation and hypotension, have not been caused by guaco. The only fetal changes observed were due to the maternal hypertension. Some studies have reported vasodilator and hypotensive effects of guaco. However, only a few studies exist, and its actual effects remain unknown. Specific studies should be developed with higher doses of guaco for a definitive conclusion of its toxic and non-toxic effects.

Toxic effects of glibenclamide in fetuses of normoglycemic rats: an alternative therapy for gestational diabetes mellitus.

Gestational diabetes mellitus (GDM) is defined as glucose intolerance first diagnosed during the second or third trimester of pregnancy. The treatment aims at glycemic control through changes in the patient's diet with or without exercise, but some patients need insulin therapy. An alternative would be to use oral hypoglycemic agents such as glibenclamide (GLIB). The present study aims to analyze the toxic effects of GLIB in fetuses of pregnant rats which received 5 or 20mg/kg doses of GLIB. Glycemic dosage reveals no significant difference between control (deionized water) and treated groups, showing that these concentrations of GLIB were not effective to cause hypoglycemia in rats. The vitality of the fetuses in all groups was 100%. GLIB administration promoted increase in weight and significant changes in measures of external morphological parameters of treated fetuses. Histological analysis revealed that liver lobes, lobules and central lobular veins were well defined for all treatments. However, GLIB animals presented a light brownish precipitate into the center-lobular veins and in the liver parenchyma among the hepatocytes. These results indicated a possible passage of the drug through the blood-placental membrane, without serious changes that impair the development of neither bone tissue, nor the liver of these animals.

Pharmacological and partial biochemical characterization of Bmaj-9 isolated from Bothrops marajoensis snake venom

Bmaj-9, a basic PLA2 (13679.33 Da), was isolated from Bothrops marajoensis snake venom through only one chromatographic step in reversed phase HPLC on »-Bondapak C-18 column. The amino acid composition showed that Bmaj-9 had a high content of Lys, His, and Arg, typical of a basic PLA2. The sequence of Bmaj-9 contains 124 amino acid residues with a pI value of 8.55, such as DLWQWGQMIL KETGKLPFSY YTAYGCYCGW GGRGGKPKAD TDRCCFVHDC, revealing a high homology with Asp49 PLA2 from other snake venoms. It also exhibited a pronounced phospholipase A2 activity when compared with crude venom. In chick biventer cervicis preparations, the time for 50 percent and 100 percent neuromuscular paralysis was respectively (in minutes): 110 ± 10 (1 µg/mL); 40 ± 6 and 90 ± 2 (5 µg/mL); 30 ± 3 and 70 ± 5 (10 µg/mL); 42 ± 1 and 60 ± 2 (20 µg/mL), with no effect on the contractures elicited by either exogenous ACh (110 µM) or KCl (20 mM). Bmaj-9 (10 µg/mL) neither interfered with the muscular response to direct electrical stimulation in curarized preparations nor significantly altered the release of CK at 0, 15, 30 and 60 minutes incubations (27.4 ± 5, 74.2 ± 8, 161.0 ± 21 and 353.0 ± 47, respectively). The histological analysis showed that, even causing blockade at the maximum dosage (5 µg/mL), the toxin does not induce significant morphological alterations such as necrosis or infiltration of inflammatory cells. These results identified Bmaj-9 as a new member of the basic Asp49 PLA2 family able to interact with the motor nerve terminal membrane, thereby inducing a presynaptic neuromuscular blockade.